1. Field of the Invention
This invention relates to a wireless communication apparatus and a wireless communication method, and more particularly to a wireless communication apparatus which acknowledges the transmission of a plurality of packets in a lump.
2. Description of the Related Art
The IEEE 802.11n standard, a standard for next-generation high-speed wireless local area network (LAN), is now being developed by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 committee.
In the IEEE 802.11n standard, a partial state block acknowledgement function obtained by simplifying the block acknowledgement function has been employed. The block acknowledgement function has been described in, for example, “IEEE Standard for Information technology—Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements,” Internet URL: ieeexplore.ieee.org/xpl/tocresult.jsp?isnumber=32891& is Year=0. In the partial state block acknowledgement function, when a plurality of data items differing in data transmitters or traffic identifiers have been received, the management area is set free by discarding acknowledge information on another data held until then in the management area. Then, acknowledgement information on new data is held in the same management area. The details of this method has been described in, for example, “IEEE P802.11n/D1.0 Draft Amendment to STANDARD [FOR] Information Technology—Telecommunications and information exchange between systems—Local and Metropolitan networks—Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Enhancements for Higher Throughput,” Internet URL: grouper.ieee.org/groups/802/11/. With the method, making full use of the same management area enables the block acknowledgement function to be realized with at least one management area for acknowledgement information.
With the above methods, however, acknowledgement information might be discarded before the transmission of data is acknowledged, or although data has not been transmitted properly. In this case, the communication apparatus which has received the data has to acknowledge the transmission of data by informing the transmitter that the data has not been received. As a result, the following problem has arisen: already received data is also transmitted again, decreasing the transmitting efficiency.